JPS5951514A - Method of producing reduced reoxidation type semiconductor porcelain condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a reduction-reoxidation type semiconductor ceramic capacitor.

Conventionally, reduction and reoxidation type semiconductor ceramic capacitors have been made by forming a reoxidation layer on the surface of a disk-shaped semiconductor ceramic to form a dielectric material, and forming an electrode on the opposite surface.
J11 was proposed and put into practical use.

This type of capacitor is relatively small yet has a large capacity, and like other ceramic capacitors, it is non-polar.
Although it has advantages such as good heat resistance and frequency characteristics, low leakage current, and low cost, the areal capacity is still only about 300nF/cr&.
When the capacitance becomes large, around 1 μF, there is a problem that the shape becomes large. A means to solve the problem in this reduction and reoxidation type 5'1:4'r'j capacitor and [7'' (non-O) on the surface of the disk-shaped reduction and reoxidation type semiconductor porcelain material. A capacitor with this structure has been proposed to have a plate-shaped reduction and reoxidation 2 (!! The capacity can be approximately doubled by using
After reoxidation treatment, it is necessary to scrape off the oxide layer formed on the surface of the semiconductor porcelain by about 30 to 50 microns to expose the internal semiconductor part. Lamp polishing, sandblasting, and laser processing are used to remove the gold reoxidation layer. Even if such methods were adopted, there was a problem that they lacked mass productivity and could not be put to practical use.

The present invention was made in view of these problems, and aims to provide a method for easily mass-producing small-sized, large-capacity reduction-reoxidation type semiconductor ceramic capacitors. A plate-like body having a plurality of convex portions on at least one surface is formed using a type semiconductor ceramic material, and after the plate-like body is subjected to reduction and reoxidation treatment, the convex portions are mechanically removed to expose the semiconductor portion. A method for manufacturing a reduction and reoxidation type semiconductor ceramic capacitor, characterized in that an ohmic electrode is formed in the semiconductor portion.

That is, the present invention focuses on the fact that porcelain is hard but brittle, and instead of polishing or grinding, a convex portion is formed in advance on at least one surface of the disk-shaped or square plate-shaped surface Ri'f. The semiconductor portion inside the semiconductor ceramic is exposed by destroying the convex portion.

Hereinafter, the present invention will be specifically described with reference to the drawings in Appendixes F and I.

FIG. 1 shows a reduction and reoxidation type semiconductor ceramic capacitor manufactured by the method of the present invention. It consists of an electrode 4 and an ohmic electrode 6 formed on its semiconductor portion 5''. This plate-shaped semiconductor sensor R52 may have either a disk shape or a square plate shape.

According to the present invention, the capacitor having the above structure can be manufactured as follows.

That is, first, a reduced and reoxidized semiconductor porcelain material, for example, BaTiO3-BaZrO3-based semiconductor porcelain paulownia material, is formed into a sheet shape, and the formed sheet is punched to form a circle having a plurality of convex portions 12 on at least one surface. A plate-shaped or square plate-shaped chip 11 is formed (see FIG. 2(a)). The convex portions 12 can be formed by processing the die of the press++i molding machine, or by stamping during or after punching. Then in air, 1200
11 in a reducing atmosphere after firing at a temperature of ~1400C.
It is made into a semiconductor by reduction heat treatment at 00 to 1200 tZ', and then reoxidized at 800 to 100 OC to form an oxide layer 3 on its surface (see middle part of Figure 2). Next, a non-ohmic electrode material t1 such as silver paste is applied to the surface opposite to the convex side surface and baked to form a non-ohmic electrode 4 (see FIG. 2 (c)). The part is destroyed mechanically, for example, by rubbing the convex side surface against the file surface of a sand vapor, etc., to expose the internal semiconductor part 5 (see 'f221M)), and on the semiconductor part, For example, Ag-Zn-Sb ohmic
A capacitor having the structure shown in FIG. 1 is obtained by forming the ohmic electrode 6 with the electrode material.

Note that although the convex part 12 can be easily destroyed, in order to expose the internal semiconductor part 5, its height is larger than the thickness of the reoxidation layer (insulator layer) 3 (usually around 30 μm). Therefore, it is desirable that the thickness be at least 50μ.

Although the figure shows the case of a plate-shaped body in which a plurality of parallel convex portions are provided on the square plate-shaped chip 11, a disk-shaped chip can also be manufactured in the same manner, and the convex portions may be arranged in parallel. Instead of forming them, they may be formed concentrically. Furthermore, convex portions may be formed on both surfaces of the chip, and ohmic electrodes may be formed on both sides of the chip. In this case, the non-ohmic electrode may be formed on the end face of the porcelain. in this way,
When ohmic electrodes are formed on both surfaces of a plate-shaped semiconductor magnetic product,
The capacity increases by about 1.5 times compared to the case shown in FIG.

Example BaTiO3 (85 monoLz%) and BaZrO3
A binder was added to a raw material consisting of a main component consisting of (15 mol%) and a trace amount of mineralizing agent. Using this mixed raw material, extrusion molding was performed using [1 gold] with unevenness on one side, and after cutting into a predetermined length, it was fired in air at 13500°C and reduced at 1100°C.

The obtained /2-porcelain had the shape shown in FIG. 2(a), its dimensions were 12 mm x 8 mm x 1.4 rrrm, and the height of the convex portion was approximately Q, 2Tl@.

Next, it is reoxidized with 9500, and then a non-ohmic electrode paste is applied to the uneven surface and the surface opposite to this uneven surface.
Burnt with C.

Afterwards, a file was applied to the uneven surface and the protrusions were partially removed. An ohmic quasi-polar paste was applied to this scraped part and baked at 500C.

The capacitance of the obtained capacitor is 0.72μF, tia
nδ (frequency I KHz) was 2.8%.

As is clear from the following explanation, according to the method of the present invention, the convex portion can be easily destroyed and the semiconductor portion can be exposed simply by applying an external force to the convex portion, and therefore an ohmic electrode can be easily formed. Therefore, an excellent effect can be obtained in that small-sized, large-capacity reduction-reoxidation type semiconductor ceramic capacitors can be mass-produced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a reduction-reoxidation type semiconductor ceramic capacitor manufactured by the method of the present invention, and FIG. 2 is an explanatory view showing the manufacturing process. ■・・・Reduction-reoxidation type semiconductor ceramic capacitor, 2...
Plate-shaped reduction and reoxidation type semiconductor porcelain, 3... reoxidation layer, 4.
・Non-oats, sex -1! , pole, 5...semiconductor 8 part, 6
... Ohmic ° [E pole, 11... Chip, 12...
・Protrusion.

Claims (3)

[Claims] (1) Reduction-reoxidation type semiconductor feeling? A plate-like body having a plurality of convex portions on at least one surface is formed using Iij +A' I+, and after reduction and reoxidation treatment of the plate-like body, the convex portions are mechanically removed to expose the semiconductor portion. A method for manufacturing a reduction and reoxidation type semiconductor ceramic capacitor, which is characterized in that an ohmic electrode is formed in the semiconductor portion. (2) The method according to claim 1, wherein the reduced and reoxidized semiconductor porcelain material is formed into a disk having a plurality of convex portions on at least one surface thereof. (3) The method according to claim 1, wherein the reduced and reoxidized semiconductor ceramic material is used to form a square plate having a plurality of convex portions on at least one surface.